Stereoscopic plate shifter



July 4, 1933.. M. MORRISON STEREOSGOPIC PLATE SHIFTER Filed Sept. 3, 1951 4 Sheets-Sheet 1 July 4, 1933. M, MORRISON STEREOSCOPIC PLATE SHIFTER Filed Sept. 5, 19

31 4 Sheets-Sheet 2 July 4, 1933. M. MORRISON STEREOSCOPIC PLATE SHIFTER 4 Sheets-Sheet 3 Filed Sept. 3, 1931 July 4, M M R QN STEREOSCOPIC PLATE SHIFTER Filed Sept. 3, 1951 .4 Sheets-Sheet 4 VVVV BY m I 6,0 ATTORN Patented July 4, 1933 NITED STATES JVIONTFORD MORRISON, or MONTGLAIR, NEWTJER-SEY,'ASSIG1\TOR 'ro wnsriiver-rousn X-RAY ooivrrAivY, mo, A CORPORATION or DELAWARE STEREOSCOPIO PLATE SHIFTER Application filed September 3, 1931. Serial No. 560.033.

My invention relates to plate changers and particularly to the type commonly utilized cally shifted after each exposure simultaneously with the movement of the X+raytube in order that the resulting pictures being taken from dilferent angles may be viewed stereoscopically through apair of mirrors thus making the pictures stand out in relief. It is imperative that the film to be exposed properly aligns with the object to be radiographed and the X-ray tube and that the exposed film be properly shieldedfrom the -X-rays to prevent a double exposure. For

this reason. in shifting the films from one position to the other it must be done as expeditiously as possible and with a total absence of any vibratory movement after completion of the shift.

1 It is, therefore,- an object of my invention to provide a plate changer which may be utilized with an X-ray tube for exposing a plurality of sensitized films to produce a stereoscopic effect.

Another object of my invention is the provision of a plate changer for shifting a plurality of sensitized films to successively position the same for exposure to X-rays.

Another object of my invention is the provision of a plate changer for automatically shifting a series of sensitized platesin position with an object to be radiographed.

Another object of my invention is the provision of a plate changer whichperforms a plurality of operations in theproper sequence ant. at predetermined periods of time.

A further object of my invention is the provision of a plate changerfor successively positioning a series of sensitized films in which the operation is entirely automatic after initial operation by an operator and in which there is an absoluteabsence of vibratory motion of the device-upon completion of the shift. Y

Still further objects of my invention will become apparent to those' skilled in the art ot ric by referenceto the accompanying drawings wherein: I

Figure l isa front elevational view of my plate changer- .With a portion thereof broken away to better illustrate the device;

Figure 2 is aside elevational view of the device; 7

-Figure 3 is a front elevational view on an enlarged scale of a portion of my plate changer; i

' Figure 4 is a sectional viewtaken on the line 1VIVIof Fig. 3;

Figure 5 is asectional view taken on the line V V of Fig. 3; r

Figure 6 is asectional view taken on the line VI.VI of Fig. 4t on an-jenlarged scale showing the details of the brake mechanism of my device. V

Figure 4 is a detailed sectional viewon an' enlarged-scale-of the reversing switch I employ withiny plate changer; V

Figure 8 is a detailed view of the contact finger of my reversing switchtaken on line VIIIVIII of'Figx'Y; I

Figure" 9 is an end view of my reversing switch, when assembled and p I Figure 10 is a diagrammatical view ofthe circuit utilized with myplate changer. V

Referring nowto the drawings in detail I have sh'own'in Fig. 1 a base member 5 upon which are mounted apair of uprights 6 and v A yoke 8 rigidly supports these upright-s l. at their upper eiztremity and a pair of angular braces or tie rods 9 and 10 assist in maintaining the uprights 6 and 7 in a rigid vertical position. A pair of angularly extending uprights 12 and 13 are disposed between the yoke 8 and base 5" and act as guide rails for a counterweight 14.

Each of the vertical uprights 6 and 7 are provided with loosely fitting sleeves or collars 15 which are arranged'to be moved vertically of these uprights. A horizontally disposed casing 16 is rigidly supported to these collars 15 .bymeans of studs 17 and a pair of chains or cables 18 are'secured to the casing 16 and pass over a pair of pulleys 19 to the counterweight 1 1. A hand wheel 20 is secured to a shaft 22 upon which the pulleys 19 are secured for the purpose of adjusting the counter-balanced casing vertically of the uprights 6 and 7.

. The casing 16 isof'a sufficient depth to house the platechanging mechanism now about to be described and is provided with a pair of hinged doors 23 exactly-alike as can beappreclated from Fig. 4. These doors'are made of, or lined with, a material 1mperv1ous to X-r-ays such as lead and together constitute v approximately two thirds of the total width The remaining one thirdis a section 24 disposed between these two door.

of this casing.

sections and is pervious to Xtrays.

A pair of rods 25 extend horizontally of the interior of the casing 16 and a cassette or'filin.

holding carriage 26 having a width approxi mating that of twothirds the casing 16'isar ranged to be moved longitudinally of these rods and carry a plurality of sensitized films. This carriage'is provided with a pair'of fixed rollers 27 which en gage the lowermost rod 25 and a pair of rollers 28 which engage the upper rod 25. These latter rollers 23 are-carried by pivoted arms 29 'aflixed to the carriage and are caused to engage the. upper rod25fby the pressure exerted by a pair of springs 30. This construction allows the ready removal of thecarri-age 26 from the casing 16;

A coil spring 32 is secured at 33 to theright hand end of the casing 16 and to the back of the lower left hand corner 34 of the carriage 26 as viewed from Figs. 1, 3 and 4. r A similar coil spring 35 is secured at the left handcorner 36 of the casing and to'the lower right handcorner 37 of the carriage. The tension of the respective springs 32 and 35 thus op pose each other and tend to equalize whenthe carriage 26 is centrally disposedrelative to the. casing 16.

A rearwardly extending pin 38 is secured to, the back of the carriage 26 at approximate ly the center of the width thereof and a crankshaft or link 39 is'journa'led to rotate about this pin38. .A vertically extending rod 40 is centrally disposed relative to the casing-16 and is rigidly secured thereto.

A loose collar 42 surrounds this rod 40 and isprovided with a laterally extending pin 43 toiwhich the other end of the crankshaft 39 is rotatably secured In order to move this latter collar 42 vertically of the rod 40 and thus cause the crankshaft 39 to move the carriage 26 horizontally upon the rods 25 I provide the collar 42 with a segmental rack 44 (see Figs. 5 and 6) Anelectric motor 45 is rigidly'supported upon a bracket 46 in the rear of the casing 16 and a horizontalshaft 47 is journaled in suitable bearings; such as ball bearings 48 (Fig. 6). The shaft 47 extends each side i of the bearings 48 and is connected at one end to the shaft of motor 45 by means of a suitable coupling-49 while its other end is provided with a threaded portion 50 for a purpose to be hereinafter described.

A pinion gear 52 is rigidlyisecured to the shaft 47 and is positioned to engage the segmental rack 44. In this manner rotation of the motor 45 causes thecollar 421:0 move up and down upon the rod-40 and move the carriage 26 back and forth-relative to the casing 16. This movement of the carriage places one or the other ofthe respective springs 32 or 35 under tension depending upon the direction of movement thereof and the purpose of. these springs and their cooperation in the arranged to moveback and forth in a cylinder 55. This'cylinder is secured to a face plate 56; by any suitablemeans such as screws 57,

and the face plate is in turn secured to the supporting bracket 46 carrying the motor;

45; by suitable means such as screws 58.

The-shaft 47 extends loosely through the face plate'56 to allow the exhausting of airtherebetween and a pair of guidepins or studs 59 secured to the face plate extend looselythrough one head of the piston 54 to prevent rotation of the same when the shaft 47 is rotated. In this manner upon rotation of the shaft 47-the piston will not rotate therewith but will be moved longitudinally of the shaft 47' and cylinder upon the guide pins 59.

The head of the piston 54 through which the threaded portion 50 of the shaft 47 passes, is provided with an annular-groove 60 and a sealing ring'62 is disposed therein which has a cross sectional area slightly less than the groove 60. The purposeof this. ring is to prevent any appreciableamount of air that IS compressed in the chamber A by movement ofthe piston to the right as viewed from Fig.6, from enteri'ngfthe chamber B through a hole 61 in the head of the piston 54; There will, howevenbe some air forced into the hollow portion of the piston due to the lo oseness of the guide pins 59 but this amount will be small and of infinitesimal consequence as the greater portion will be enhausted through the loose opening pro- Vlded between the shaft 47 "and. face plate 56.

1 The cylinder 55 is provided with a suitable spring pressed ball check 63 to allow for the intake of air during movement of the pistonin one direction and an adjustable needle" valve 64 is provided to allow exhausting of the air during the reverse movement of the piston'by the remaining piston head. This piston acts asa combination brake and shock absorber to prevent any vibratory action of the carriage 26 when the latter has reached its limit of travel in either direction and causes the films to remain fixed in alignment with the previous section of the casing 16.

Themotor 45 initiates the movement of the carriage 26 to compensate for the inertia required to start this movement and one of the respective'springs 32 or 35, depending upon which is under tension, assists the action of'the motor. When the carriage has moved a suflicient distance to permit the pin 38 to pass to the right of the rod 40 the motoris automatically shut off by means of a switch mechanism '65 now about to be described. The energy of one of the respective springs 32 or 35 is then suflicient to continue the move ment of the carriage 26 until the motor is finally deenergized and the aforementioned brake mechanism stops the carriage at the proper location.

Referring now more particularly to Figs. 7, 8, 9 and'l0 I have shown a switch together with a plurality of circuits which I utilize with myplate changer for operating the electric motor 45. A pair ofsegm'ental blocks in their normal operating position they are in a parallel position as shown in Figs. 1, ,3,

j 7 and 9.

with a similar number of arcuate metallic strips 74, 75, 76, 77, 78and 79. In order to establish contact between these various metallic strips to complete the circuits to the motor 45 I provide an insulated block 80 which is ournaled upon the pin 38 and secured to the front of thecrankshaft 39 by means of a pin or set screw 31. This block 80 is provided' with a pair of contact strips 82 and 83 each of which are provided with a plurality of contact fingers 84, 85 and 86, 87 respec tively.

When the block 80 rotates with the crankshaft 39 about the pin 38 the contact finger .84 makes contact successively with the arcuate strips 69, 70, 71, 72 anc 73, while the The insulated block 67 is likewise provided contact finger 85 maintains contactwith the elongated strips 68. In a like manner during rotation of the block 80 the contact finger 86 makes successive contact with the respective strips 7 5, 76,77, 78 and 79, while the finger obvious that during movement of the carriage 26 in either direction the switch, represented generally at 65, is caused to successively open and close a plurality of circuits by the movement thereof by the crankshaft 103 which are connected to one end of the field windings F1 and F2 of motor 45. A double pole double throw control switch, represented generally at 104, is positioned in a convenient location and is providedwith a series of contact terminals 105, 106, 107, 108 which in operation are adapted to be engaged by one of the switch blades 109 and another set of contact terminals 110, 112, 113, and 114 adapted to be contacted during operation by the remaining switch blade 115. v

A conductor 116 extends from the remaining end of the field winding F1 to the switch blade and a similar conductor 117 connects the remaining end of the field winding F 2 to the other switch blade 109. A conductor118 extends from one terminal of the armature of motor 45 to the arcuate metallic strip 68 carried by the insulated block 66 and another conductor 119 extends from the remaining armature terminal to the strip 74 carried by the block 67 A conductor 120 connects the terminal 105 of the control' switch 104 to the strip 69, carried by block 66, and a conductor 122 connects the switch terminal 110 to the strip 75 of block 67 Aconductor 123 connects the terminal 107 of the switch 104 to strip 72 carried by block 66, and a conductor 124 interconnects strip 72 with the-strip 76 carried by the block 67.

The switch terminal 113 is connected by means of a conductor 125 to the strip 70 of block 66 and a conductor 126 interconnects thislatter strip with strip 78 0f block 67 Likewise a conductor 127 connects the switch terminal 108 with the strip 73 of block 66 and a conductor 128 connects the switch terminal 114 with strip 79 of block 67 A Switch terminal 106 is bridged with terminal 113 by means of a conductor 129 and the switch terminal 107 is likewise interconnected by means of a conductor 130 with terminal 112 for reversing'the direction of movement of carriage 26 as hereinafter explained...

Assuming now it is desired to take a radiographic exposure of an object my plate changes is leveled upon the floor by suitable means, such as adjusting screws secured to the base 5, and the casing 16 is adjusted vertically upon the standards 6 and 7 by means of the hand wheel 20 until the pervious I of set screws 136 as shown in Figs. 4- and 5.

The carriage 26 is then loaded with sensitized films through the hinged doors23 and the same is moved to one or, theother'of its limits of travel inthe casing 16 such as to the left, as shownin Figs. 1,- 3'and l, which permits one 01 the films. to align with theimpervious section '24 ofthe casin The X ray tube (not shown) is then energizedin a; suitable mannerand the, image registers upon the film. I A

Upon deenergizing the X-ray tube the hand switch 104 is then closed to the left as Viewed in Fig. 10. This causes the switch blade 109 to establish-contact withtlie'respective switch terminals 105 and 106 and the switch blade 4 and 112. a y a 'Assumingthe carriage 26 is in the position just mentioned tl e insulated block afiixed tocrankshai't 39 will have its contact fingers in contactwith the arcuate metallic strips carried by the insulated blocks and 67 in the following manner. Contact linger 8 1 will establish a connection with strip 69 and finger will establish a connectionwith the which maybe traced as follows: from the source of energy 100, through theconductor 102, to field winding F2 and thence through conductorll? to the switch blade 109. At this point the circuit divides a portion thereof extendingfroin the switch terminal 105, conductor 120 to the metallic strip 69, through contact fin er 8 1- to contact finger 85 which is in contact with strip 68, thence through conductor 118 to the armature of motor 15, through conductor 119 to the strip 74 carried by bloclr6T, then through contact fingers 86 and 87 to the strip 715, through conductor 122 to switchterminal 110, through blade 115 and conductor 116 to the field winding F1 and thence back to the source through conductor 103.

The motor e5 will rotate the shaft li'carrying the pinion gear 52, which engages the rack 44 car 'ied by collar 42, and moves this latter .collar vertically upon the rod 40. Movement of the-collar 42 rotates the'crankr shaft 39 about the respective pins 38,43 and draws the carriage toward the right upon the rods 25. rl'pon rotation oi'tthe crankshaft 39 about the pin 38 the insulated block 80 11;) .to likewise establish contact. with the respective SWltCiI terminals which is secured thereto by means-of the pin 81 willlikewise rotate. This causes the respective contact fingers 84; and 86 to pass from the respective metallic strips 69, 75 to the strips 70, 76.

The motor 45, however,'continues to run because that portion of thecircuit extending from the switch terminals 105 and 1lO to the contact strips 69,75 is'reestablished in the following manner: from the switch terminal106-through conductor 129 to the switch terminal 113, then by means of conductor to the strip 70 and from switch terminal 112 throu 'hconductor to the switch terminal 10'! v and thence by means of conductor 123 and 12% to the strip 7 6. This reestablishes that portion 01' the circuit interrupted by rotation of the contact block 80 and as the I spective strips 71, 77L These latter strips not a being supplied with energy from the source are dead and consequently the motor cir-' cuit is interrupted thereby deenergizing the motor;v

A lthough the motor is now deenergized the carriage 26 will continue its movement in the initial direction due to its momentum and the potential energy of one of the springs 2, which in theoperation heretofore jassuined would be the spring 32 now under tension rotate the block 80 still further until the contact fingers s4 and 86 engage the respective strips 72 and 78. These latter strips are connected by means of conductors-124 and 126 to the strips 76 and 70 respectively which again completes a circuit to the'motor 45 in the same manner as previously traced with one exception, however, which is that the direction of flow of the energy through the armature ofthe motor is reversed thereby reversing'the' direction of rotation of the motor.

This reversal of the motor may be appreciated by noting that the armature of the motor is connectedto the respective'strips 68 and .74: and when the strip 68 is energized through the contact fingers 84; and 85 from the strip 70 it receives current of one polarity which may be assumed to bepositive current. Likewise when the strip 74 is energized through the contact fingers 86,87 from This movement of'the carriage will the strip 7 6 it receives current'of an opposite polarity or. negative current. I

In providing the conductors 124 and 126 which, as before "explained, interconnect the respective strips 76', 72 and70, 78, current of an opposite polarity is thus caused to flow to the respective strips 68, 7 4 and to the armature fronrthat which flowed during the former energization of the motor.

The motor 45 will, therefore, be again energized but rotates in an opposite direction to force the collar 42 in a downward direction. This movement, however, continues to force thejcarriage 26 in its initial direction as the pin 38 will at this time have passed to the right of the rod 40 a suflicient distance to enable the thrust'of the crankshaft 39 to be in the same direct-ion and it i will continue to rotate in the same direction.

Further rotation of the crankshaft 39 also rotates the block 80 until the contact fingers 84 and 86 establish a connection with the strips 73 and 79 respectively. These latter strips, being connected by means of the conductors 127 and 128 to the respective switch terminals 108 and 114, .are now dead as the switch blades 109 and 115 are not in contact therewith andconsequently the circuit to themotor is again interrupted.

The carriage 26 has, however, now reached itsextreme, limit of travel inthis direction and the sensitized film which was formerly disposed in back of the left hand impervious section 23 (Figs. 1,3 and 4), is now aligned with the pervious section 24 and the exposed film is positioned in back of the right hand impervious section 23, The X-ray tube may, therefore, be shifted to a different angle rela tive to the object and again energized inany suit-able manner to expose the patient to an other radiographic picture in order to study the resulting'pictures in a stereoscopic device.

During the rotation of the shaft 47 by the motor 45 the double headed piston 54 is moved longitudinally of the cylinder 55 upon the guide pins 59 by the engagement of the piston with the threaded portion 50 ofthe shaft. e

The air containedin chamber A of the cylinder 55 ahead of the piston isthusslowly forced out through the loose opening between the shaft 47 and face plate 56 and air is slowly drawn-into the chamberB through valves '63. l Vhen the piston is moved in the opposite direction air is forced out of chamber B through the needle valve 64 and is drawn into chamber A through the same opening as thattl'rrough which exhaust follows movement of the piston in the other-direction of movement. As the piston moves in either directionof movement the sealing ring 62 will be forced into a direction opposite to that of the movement ofthe piston thereby substantially closing the gap 60.

The slight leakage of air around the pins59 is allowed to pass into the opposite chamber through the opening 61 to assist in absorbing the shock.

The entire mechanism comprising the motor 45, collar 42, crankshaft 39 and carriage 26 is therefore'brought to a gradual position of rest with an entire absence of vibratory movement when the motor 45 isv deenergized. The mechanism is likewise maintained in the desired location through the medium of the brake 53 together with the mechanical connection of the pinion'gear 52 and rack 44. I V

When it is desired to cause the carriage to move in a direction opposite to that previously assumed, that is to say from right toleft,

the hand switch is moved-to the. right as viewed from Fig..10.,This enables the switch blade 109 to establish a contact-with the terminals 107 and 108, and the blade 115' to contact the terminals 113, 114 to again cause the motor 45 to become energized through the conductors 127 and 128.

' Inthis position of the switch-the strips 7 and 7 9 receive energy and the remainder of the circuit to the motor is completed in the same manner as previously described. During the rotation of the crankshaft 89 carrying the block in the opposite direction the identical cycle of operations follow as was described during movement of the carriage 26 from left to right. 7

It must be appreciated that the length of the arcuate metallic strips 69, 70, 71, 72, 73

carriedby the insulated block 66 and the Sim-' ilar strips5, 6, 77, 7 8 and 79 carried by the block 67 are so apportioned relative tothe speed of motor 45 and the length of travel of the carriage 26 that the aforementioned se-;

quence of operation takes place at predetermined time intervals. Likewise itmust be understood that this sequence of operations 'follow'each other in rapidsuccession and that the entire period of time required to shift the carriage 26within the casing 16 is of relatively short duration.

It can thus be readily seen by those skilled in the art that I have provided a radiographic plate-changer for exposing a pluralityof-sem sitized films in rapid succession to a suitable source of X-rays and in which the shifting of the plate is accomplished with accuracy in properly aligning the films with the pervious and impervious sections of the casing and with an entire absence of vibratory mo- 7 is brought to'a position when the carriage tion of rest. 7 v a.

Although I have shown and described one specific embodiment of my invention I do not.

desire to be limted thereto as various other modifications of the same may be made without departing from the spirit and scope'of the appended claims. a

What is claimed is:

1. In a radiographic plate changer, a casmg, a carr age mounted for reciprocatory.

CIT

states said pinion gear. is

' 'ciprocatory movement in a plane at right angles to'andcrossing the plane vvof movement of said carriagda crankshaft interconnectingsaid operatingmember and said carriage, means "connected to said operating member to impart reeiprocatory movement thereto and to said carriage through said. V-crankshaft, and meanseperable upon movement of'said carriage for reversing the movementof 'saidiirst mentioned means and said operating member after said carriage has moved a predetermined distance. a

8. In a radiographic plate changer, a carriage mounted for reciprocatorymovement in a single plane, an operating member mounted for reciprocatory movement in a plane at right angles to and crossing the "plane of movement of said carriage, a crankshaft interconnecting said operating member and said carriage, means for mov ng said opera-ting membertoimpart reciprocatory movement thereto and to said carrlage, and

means carried upon said carriage operable bye'the simultaneous movement of said crankshaft and carriage'for reversing the movement of said first mentioned means and said operating m'ember When the greater portion of said carriage has crossed the plane of movement of said operating memben 4. In a radiographic plate changer, a carriage mounted to move in a single: planeupon gu de rods, an operating member provided,

with a gear rack arranged to be-moved in a I single plane upon a guide rod at right angles 7 to the plane of movement of said carriage, a V crankshaft interconnecting said operating member "and said carriage, and an electric motor provided with apinion gear engaging saidgear rack for causing said operating member to move upon its guide rod and to move saidcarriage upon its respective guide rods when said motor is energized vand ro- "5. In a ra'diographic plate'changer; acerriage mounted to move in a single plane upon guide irods, an operating member provided gwith a es;- rack'arranged to bemoved in a single plane upon a guide rod at rightangles to the plane of movement" of said carriage, a crankshaft interconnecting said operating member andsaig'zl carriage, an electric motor provided With a pinion'gearengaging said ciprocatory movement a single plane upon guide rods ln'said frame member, an opert X Tays and a plurality of sections imgear rack for causing said operating memberito move upon its guide rod and to move said carriage upon its respective guide rods, and an electric switch mechanically connect a cd to'said crankshaft and electrically connected tosaid meter for controlling said motor by the movement of said carriage. "6. In a; radiograph-ic plate changer, a carria' 'e mounted to move in a single planeupon guide rods,,an operating member provided with a gear rack arranged to be moved in, a single planeupon a guide rod at right angles to the plane of movement of said carriage, a crankshaft interconnecting said operating i-- member and said carriage, an electric motor provided With a vpinion gearengaging'said gear rack forcaus'ingsaid operatingmember remove upon its guiderodand to move said carriage'upon'its respective guide'rods, and or a brakemounted upon the shaft ofsaid motor for arresting the movement of said'operating 7 member "and said carriage. I g 7 7.,I-n radiographic' plate changer, a frame member, a carriage mounted formating member mounted for reciprocatory I movement in a single plane upon a guide rod at right angles to the movement-of said carriage, a crankshaft interconnecting said op v crating member and said carriage, an ielectric motor connected "to said operating memher for initiating'movement of said operating member and said carriageupon their respective guide rods,'an'd a spring connected to said carriage and "to said frame member for continuing themovement ofsaid carriage after. initial movement bysa'idmotor.

' 8; A 'radiographic plate changer comprisvinga casing provided With sections pervious and impervious-to X-rays,a carriage adapt:

ed to. holda plurality of sensitized films and arranged for reciprocatory movement disposed in said casing with a portion of said all, I U

films in alignment with the .pervious section and the remainder thereof in alignment with the impervious'section ofsaid casing, anvop crating member arranged for reciprocatory nio'remen't'at right angles; to the movement g 'ofsaid'carriage, means connected to said operating member for causing-reciprocatory vmovementthereof, means interconnecting sardoperatmgmember and sald carriage for ransmitting reciprocatory movement to the latter upon" movement of sald operating member to alter the position of said films reliative to said sections, and means associated with said carriage and operableupon movement thereof for reversing the directionof said first mentioned means and said: operating memberafter said carriage has moved a predetermined distance. a j r i.

9. vAradiographic plate changer compr-ising a casing provided with a section pervious h pervious to X-rays, a carriage adapted to hold a plurality of sensitized films and arranged for reciprocatory movement disposed in said casing with a portion of said films in alignment with the pervious section and the remainder thereof in alignment with one of the impervious sections of said casing, an operating member carried by said casing and arranged for reciprocatory movement at posure thereof to X-rays and the remaining film with the pervious section of said casing.

10. A radiographic plate changer comprising a casing provided with a section pervious to X-rays and a plurality of sections impervious to X-rays, a carriage adapted to hold a plurality of sensitized films and arranged for reciprocatory movement disposed in said casing with a portion of said films in alignment with the pervious section and the re-- mainder thereof in alignment with one of the impervious sections of said casing, an operating member carried by said casing and arranged for reciprocatory movement at right angles to the movement of said carriage, means connected to said operating member for causing reciprocatory movement thereof, means interconnecting said operating member and said carriage for transmit ting reciprocatory movement to the latter upon movement of said operating member to alter the position of said film relative to said sections, means assoclated with said carriage v and operable upon movement thereof for reversing the direction of said first mentioned means and said operating member and rendering the same ineffective to cause movement of said operating member after said carriage has movedto align one of said films with the remaining impervious section of said casing after exposure thereof toXrays and the remaining film with the pervious section of said casing, and means associated with said first mentioned means for arresting the movement of said operating member and carriage after the latter has moved a predetermined distance ineither directions of travel. 7

11'. In a positively driven radiographic plate changer the combination of, a casing provided with a carriage mounted for recip rocatory movement in a longitudinal plane relative to said casing, an operating membermounted for reciprocatory movement vin a plane at right angles .to and crossing the plane of movement of said carriage, means connected to, said operating member for causing reciprocatory movement thereof, and means interconnecting said operating memher and said carriage whereby said first men tioned means imparts simultaneous reciprocatory movement to said operating member and said carriage.

12. In a positively driven radiographic plate changer the combination of, a casing provided with a carriage mounted for reciprocatory movement in a a longitudinal plane relative to said casing, an operating member mounted for reciprocatory movementin a plane at right angles to and crossing the plane of movement of said carriage, means connected to said operating member for causing reciprocatory movement thereof, means interconnecting said operating member and said carriage whereby said first mentioned means imparts simultaneous recipro-v catory movement to said operating member and said carriage, and means operable upon thesimultaneous movement of said operating member and said carriage for reversing the movement of said first mentioned means and said operating member after said carriage has moved a predetermined distance.

13. In a positively driven radiographic platechanger the combination of, a casing provided with a carriage mounted for reciprocatory movement in a longitudinal planerelative to said casing, an operating member mounted for reciprocatory movement in a plane at right angles to and crossing the plane of movement of said carriage, means connected to said operating member formovmg the same in a predetermlned path, means interconnecting said operating member and said carriage for transmitting reciprocatory movement from said operating member to said carriage, means operable upon the simultaneous movement of said operating member and said carriage for reversing the movement of said first mentioned means after said operating member has moved a predetermined distance in its path of traveland for rendering sa d first mentioned means inefiective to cause movement of said operating' member and said carriage after the greater portion of said carriage has crossed the plane of movement. of said operating member, and

energy storage means connectedto said carriage for continuing the movement thereof to its extremity of travel after saidlastmentioned means has rendered saidffirst'mentioned means ineffective to cause further movements of said carnage.

In testlmony whereof, I have hereunto subscribed'myname this 1st day of September.

1931. uourronn MORRISON. 

